There is a misunderstanding commonly voiced around the world that languages borrow words from other languages when they lack a native word for something in their own vocabulary. This is, actually, only one reason, and not the primary one, for the existence of direct loan words.
It is certainly true that English-speaking peoples may never have run into chandeliers, vodka, tacos or toupees had the words for them not slipped into their language. But can it really be argued that the Japanese would have had no supōtsu (スポーツ, sports), sekkusu (セックス, sex) or rōn (ローン, loan) if these words had not burrowed their way into their language? If you had to do without one of the above, which one would you choose? In these days of credit crunches, I think most of us would have to say the loan.
The major source for borrowings into Japanese has overwhelmingly been English. With the tech revolution of the past two decades has come a host of words such as konpyūtā (コンピューター, computer) and netto (ネット, the Net). For the previous generation, terebi (テレビ, television) was the equivalent loan word; for the generation before that, it was rajio (ラジオ, radio).